Diakou et al. Parasites Vectors (2019) 12:519 https://doi.org/10.1186/s13071-019-3760-9 Parasites & Vectors SHORT REPORT Open Access Efcacy of a moxidectin/imidacloprid spot-on formulation (Advocate®) for the treatment of Troglostrongylus brevior in naturally infected cats in a feld study in Greece Anastasia Diakou1, Simone Morelli2, Dimitris Dimzas1, Angela Di Cesare2, Gioia Capelli3, Chiara Parrinello2, Matthias Pollmeier4, Roland Schaper4 and Donato Traversa2* Abstract Background: Troglostrongylus brevior is a lungworm of wild felids that recently has been recognized as agent of severe respiratory disease in domestic cats in Mediterranean and Balkan countries. Nevertheless, the information on treatment options for feline troglostrongylosis is still poor. The aim of this pilot feld trial was to evaluate the efcacy of the spot-on formulation containing 1% w/v moxidectin and 10% w/v imidacloprid (Advocate ® spot-on solution for cats, Bayer Animal Health GmbH) in the treatment of T. brevior infection in naturally infected cats in Greece. Methods: The trial was a negative control, multicentre, clinical efcacy study conducted according to the standards of Good Scientifc Practice (GSP). Sixteen cats in two study sites, naturally infected with T. brevior, were allocated to an untreated control group (G1, n 8) or a treatment group (G2, n 8), according to a randomization list. Animals = = assigned to G2 were treated with Advocate® for cats on days 0 and 28 at the recommended dose rate and animals assigned to G1 received a rescue treatment with the same product on days 56 and 84. Efcacy was assessed on days 28 and 56 in G2 and on days 84 and 112 in G1 by faecal larval counts. The primary efcacy criterion was the absence of T. brevior frst-stage larvae (L1) following treatment. Other efcacy parameters were the quantitative comparison of L1 presence before (baseline) and after one or two treatments in both groups. Results: All G2 cats were negative for T. brevior L1 at the frst post-treatment evaluation (100% efcacy) while G1 cats were persistently shedding L1. The diference of the mean number of L1 per gram between G2 and G1 was statisti- cally signifcant (P < 0.001). All G1 cats were negative (100% efcacy) for T. brevior L1 at the frst post-rescue-treatment evaluation. Therefore, treatment efcacy at study completion was 100% in both groups in terms of stopping the L1 shedding in the faeces of the animals. No adverse efects were observed during the study. Conclusions: These results indicate that Advocate® spot-on solution for cats represents an option for treating cats naturally infected with T. brevior. Keywords: Troglostrongylus brevior, Cat, Moxidectin, Treatment *Correspondence: [email protected] 2 Faculty of Veterinary Medicine, University of Teramo, Località Piano D’Accio snc., 64100 Teramo, Italy Full list of author information is available at the end of the article © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Diakou et al. Parasites Vectors (2019) 12:519 Page 2 of 5 Background Methods Troglostrongylus brevior, a parasitic nematode that Study design afects bronchi and bronchioles of wild felids (e.g. Felis Te study (BAH Study No.: 205121) was conducted silvestris silvestris), has recently attracted scientifc inter- according to the standards of good scientifc practice est, due to its ability to induce severe bronchopneu- (GSP) and the National Animal Welfare requirements, monia in domestic cats and its apparent spreading in with the approval of the National Organisation of Med- various countries [1]. Te parasite has an indirect life- icines of Greece (No. 25953). Te study was a nega- cycle involving a gastropod (terrestrial slugs or snails) as tive control, multicentre, partially blinded (examining intermediate host, in which the frst-stage larvae, shed investigator blinded) trial, following a randomized by the infected cat, develop into the infective third larval block design. stage (L3). Paratenic hosts (birds, rodents, reptiles) prob- ably play a key role in the biological cycle, facilitating the transmission of the parasite to the defnitive host [2]. A Pre‑inclusion screening vertical route of transmission is also known although Between study days (SD)-18 and SD-10, faecal samples it is unclear if it occurs via the utero or/and the milk of cats under null or irregular antiparasitic treatments [3]. Troglostrongylus brevior infection in cats has been for endoparasites, referred to private veterinary prac- increasingly reported since 2010 in diferent countries tices located in seven study areas, i.e. two already known of Europe, i.e. Spain, Italy, Greece, Cyprus and Bulgaria, as enzootic (Mykonos and Attica) [7] and fve with no with a prevalence ranging from 1.2% to 14% [4]. In the previous relevant information (Rhodes, Xanthi, Kavala, vast majority of cases, this lungworm has been described Tessaloniki and Syros), were subjected to qualitative in areas where the natural host of T. brevior, the Euro- Baermann’s examination. Parasite morphological features pean wildcat, is present, although infected domestic cats were identifed using published keys [1, 12]. have been found also in regions where the presence of From the cats that were found positive for T. brevior, a wildcats is not documented [4, 5]. faecal sample was collected between SD-6 and SD-3 and Cat troglostrongylosis has been proven severe and life- subjected to a quantitative Baermann test as previously threatening in kittens and young animals, as it can cause described [13, 14] to confrm the infection and determine irreversible lung damage and is a potential threat for the the baseline numbers of L1 larvae per gram of faeces litter in the case of pregnancy or lactation [1–4, 6, 7]. (LPG). Te identity of the L1 microscopically identifed To date, the only product licensed for the treatment as T. brevior was confrmed with a species-specifc PCR of T. brevior infection in cats is a spot-on formulation [6]. containing eprinomectin in combination with fpronil, (S)-methoprene and praziquantel (Broadline™ spot- on solution for cats, Boehringer Ingelheim, Ingelheim Inclusion and exclusion criteria and allocation to study am Rhein, Germany). Other anthelmintics containing groups emodepside or moxidectin have recently shown their On SD 0 the potentially enrollable cats were subjected potential efectiveness in treating T. brevior infection to veterinary examination and body weighing. Only ani- in pilot studies [8], in clinical settings [9] or in experi- mals that satisfed the following criteria were included ® mental studies on intermediate hosts [10]. Advocate in the study: (i) cats shedding at least 15 LPG of T. bre- spot-on solution for cats (Bayer Animal Health GmbH, vior between SD-7 and SD 0; (ii) cats ≥ 9 weeks of age Leverkusen, Germany) is a combination of 1% w/v mox- and weighing at least 1 kg; (iii) cats with no severe clin- idectin and 10% w/v imidacloprid, licensed globally for ical signs at physical examination on SD 0; (iv) cats for treatment and prevention of a variety of ecto- and endo- which none of the restrictions of the product label was parasites. In Europe, this product is labelled for feline applicable; (v) cats without lesions in the application area cardio-pulmonary and intestinal nematodes for preven- (base of the neck) of the investigational veterinary prod- tion (Diroflaria immitis) and/or treatment (Capillaria uct (IVP); (vi) cats for which the owner provided written aerophila, Toxocara cati and Ancylostoma tubaeforme) owner consent form. [11]. More recently it has also been labelled for preven- Animals for which the following criteria were con- tion and treatment of Aelurostrongylus abstrusus. Given frmed were excluded from the study: (i) cats showing preliminary data that have indicated the potential util- severe clinical signs compatible with T. brevior infec- ity of moxidectin in treating T. brevior infection in cats tion, for which it was estimated that the inclusion in the ® [9, 10], this study investigated the efcacy of Advocate study might have permanently compromised health; (ii) against T. brevior in naturally infected cats in enzootic pregnant or lactating cats, or cats for which mating was areas of Greece. planned within the next 16 weeks; (iii) cats with known Diakou et al. Parasites Vectors (2019) 12:519 Page 3 of 5 hypersensitivity to at least one of the ingredients of the examination. A secondary efcacy endpoint has been set I V P. based on the reduction of the LPG values from the pre- All cats meeting the inclusion and not meeting the treatment assessment (baseline) to SD 28/29 (post-treat- exclusion criteria were included in the study and ran- ment collection 1) and 56/57 (post-treatment collection domly allocated to two study groups, i.e. Group 1 (G1) 2) in cats of G2, calculated as percent reduction accord- left untreated (n = 11 cats) and Group 2 (G2) (n = 8 cats) ing to the formula: treated with Advocate®. (Pre - treatment mean LPG −Post - treatment mean LPG) Reduction (% ) = × 100 Pre - treatment mean LPG Anthelmintic treatment A further efcacy criterion was the LPG values reduc- Cats assigned to the G2 were treated twice at a monthly tion from baseline to SDs 83/84 and 111/112 in cats of interval on SD 0 and SD 28/29. To generate additional G1, calculated as above. efcacy information and for ethical reasons G1 cats Te signifcance of the diference of the mean LPG received a rescue treatment twice at a monthly interval between the two groups at each time point was assessed with Advocate® on SD 56/57 and SD 83/84.